This happened to me once but lucky for me it was before I fed and it happened because I heated it up to fast. I started a new routine becasue of it. I put them in the fridge the night before, then in the morning before work I put them in the snake room to get to room temp during the day. Then at feeding time I heat the head of the f/t with an old hair dryer. That has worked pretty well for me so far.